We propose to train MD, MD/PhD and pre-doctoral investigators in contemporary epidemiology of emerging infectious diseases and bioterrorism through instruction, practical application, and research in fundamental epidemiology, biostatistics and molecular epidemiology. For some trainees, additional training in bioinformatics or medical informatics will be offered. Trainees will be drawn from the pool of those accepted into the PhD graduate program in epidemiology at Stanford and from postdoctoral fellows in adult or pediatric infectious diseases. Trainee applicants will be evaluated by the Steering Committee and offered training grant slots on the basis of academic records, faculty interviews and demonstrated interest in epidemiology. Every effort will be made to attract minority candidates. The training program will be interdisciplinary, involving faculty from the Division of Epidemiology (Medicine (Infectious Diseases), and Pediatrics (Infectious Diseases) at Stanford and the School of Public Health, University of California/Berkeley. Predoctoral students will complete the requirements of the Stanford PhD program in epidemiology. MD or MD/PhD infectious diseases postdoctoral fellows may elect to obtain the MS degree in epidemiology, although this is not a requirement. The emphasis of the program is on research training in epidemiology of infectious diseases and bioterrorism. Trainees will conduct research under the mentorship of at least one training program faculty member; most will be co-mentored by two members of the training program. Thus, most research projects will be cross-disciplinary to take advantage of the strengths of the faculty. To promote interaction among trainees and faculty, research seminars conducted by trainees, weekly interdisciplinary seminars in infectious diseases epidemiology, weekly infectious diseases grand rounds, infectious diseases and bioterrorism lectures presented by faculty, and an annual 1-day research retreat will be held. Each trainee will be counseled and directed by a Research Committee comprised of the mentor(s) and several other scientists whose area of expertise is relevant to the project. The trainee will present his/her research progress to the committee at regular intervals. One PhD predoctoral and two MD (MD/PhD) post-doctoral trainees are to be supported by the Training Program each year. All trainees will be encouraged to apply for independent support. Trainees are expected to graduate to academic appointments or public health leadership positions.